Resin film

Abstract

To provide a resin film in which yellow discoloration caused by a production process is suppressed.SOLUTION: Provided is a resin film made of a resin composition, where the resin composition contains one or more kinds of resin selected from polyamide-imide resin, polyamide resin, polyimide resin, polyarylate resin, polyether sulfone resin and polycarbonate resin, and a predetermined phosphorus compound, where the content of the phosphorus compound is more than 0 pts.mass and 25 pts.mass or less for the resin 100 pts.mass, and the content of solvent is 2.5 pts.mass or less for the resin 100 pts.mass.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin film.

Background Art

[0002] Display devices such as smartphones and tablets are required to be thinner, lighter, and even more flexible with the rapid progress. Such display devices usually include a cover window for protecting the surface of the display, and as the cover window, a film of an organic polymer material, particularly a resin film, is widely used.

[0003] In recent years, in addition to meeting the above-mentioned requirements, the development of organic polymer materials used for the film as the cover window has been variously advanced for the purpose of further improving various properties such as toughness, heat resistance, and solvent resistance.

[0004] For example, in Patent Document 1, a polyamide film having a specific structural unit is proposed. In Patent Document 2, a polyamideimide film having a specific structural unit is proposed. Further, in Patent Document 3, a polyimide film having a specific structural unit is proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] Here, in order not to impair the display of the display, it is basically important that the film has high colorlessness and transparency. However, due to the manufacturing process, the film tends to have a yellowish tint (in other words, colorlessness is easily inhibited and yellowing is likely to occur).

[0007] In addition, in terms of the film using resin, it is not limited to the film as the cover window of the above-described display device, and is used in a wide range of fields and applications such as, for example, packaging films and various optical films. Even in such films, yellowing causes more or less disadvantages and is a problem that should be avoided as much as possible.

[0008] Therefore, an object of the present invention is to provide a resin film in which yellowing caused by the manufacturing process is suppressed.

Means for Solving the Problems

[0009] As a result of intensive studies to solve the above problems, the present inventors have found that when a film is produced by dispersing a predetermined resin in a solvent, by blending a predetermined phosphorus compound, the phosphorus compound contributes to the suppression of yellowing, and thus the present invention has been achieved.

[0010] The gist configuration of the present invention for solving the above problems is as follows.

[0011] [1] A resin film comprising a resin composition, wherein the resin composition comprises one or more resins selected from polyamideimide resin, polyamide resin, polyimide resin, polyarylate resin, polyethersulfone resin, and polycarbonate resin, and the following general formula (1):

Chemical formula

[0012] [2] The resin film according to [1], wherein the content of the phosphorus compound is 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin.

[0013] [3] The resin film according to [1] or [2], wherein the solvent is one or more selected from an amide solvent, an ester solvent, and an ether solvent.

[0014] [4] The resin film according to any one of [1] to [3], wherein the resin is one or two selected from a polyamideimide resin and a polyamide resin.

[0015] [5] The resin film according to any one of [1] to [4], wherein the phosphorus compound is one or more selected from the phosphonic acid-based compound represented by the above general formula (1) and the orthophosphate ester represented by the above general formula (2).

Advantages of the Invention

[0016] According to the present invention, it is possible to provide a resin film in which yellowing due to the manufacturing process is suppressed.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, the present invention will be exemplified and described in detail based on its embodiments.

[0018] <Resin Film> The resin film of one embodiment of the present invention (hereinafter, may be referred to as "the resin film of the present embodiment") is a resin film made of a resin composition. And the resin composition is one or more resins selected from a polyamideimide resin, a polyamide resin, a polyimide resin, a polyarylate resin, a polyethersulfone resin, and a polycarbonate resin, and The following general formula (1):

Chemical formula

Chemical formula

[0019] In such a resin film of the present embodiment, the reason why yellowing is suppressed is presumed as follows.

[0020] Usually, when a resin film is produced by a solution casting method, (1) a resin and, if necessary, additives to be blended are dispersed (dissolved) in a solvent to prepare a solution containing a resin composition, (2) such a solution is applied onto a substrate to obtain a coating film, and (3) such a coating film is heated and dried to remove the solvent. Through these steps, a resin film can be formed. At this time, since a highly polar high-boiling solvent is often used as the solvent, even if the heating and drying are carried out carefully, the solvent may remain more or less in the final film. That is, it is substantially impossible or extremely difficult to completely remove the solvent from the film. The present inventors have considered that this solvent remaining until the end is mainly colored by oxidation or the like during heating, and thus causes yellowing of the resin film itself. Incidentally, such considerations are also based on the fact that, in the intensive studies by the present inventors, a correlation was found between the amount of residual solvent in the resin film and YI (yellowness index).

[0021] Then, the present inventors further conducted repeated studies and found that when a predetermined phosphorus compound is used together with the solvent, yellowing of the resin film itself is significantly suppressed. Due to the specific action of the phosphorus compound, at least a part of the solvent remaining until the end described above is replaced by the phosphorus compound. And it is presumed that due to such replacement, the remaining amount of the solvent relatively decreases, and as a result, yellowing of the resin film itself is significantly suppressed. Incidentally, such a presumption is also based on the fact that, in the intensive studies by the present inventors, a correlation was found that the larger the blending amount of the predetermined phosphorus compound, the smaller the amount of residual solvent in the resin film produced under the same conditions.

[0022] Based on the above considerations and presumptions, by using a predetermined resin and a predetermined phosphorus compound and optimizing the contents of the phosphorus compound and the solvent, in the resin film of the present embodiment, yellowing caused by the manufacturing process can be significantly suppressed.

[0023] Furthermore, the resin film of the present embodiment may also have an effect that mechanical properties such as elastic modulus are maintained at an equivalent level in comparison with a resin film produced under the same conditions except that no predetermined phosphorus compound is used.

[0024] Incidentally, when the resin film is produced, especially during drying, not only the solvent but also the phosphorus compound can volatilize. Therefore, in the present embodiment, it is important to specify the content of the phosphorus compound and the content of the solvent in the produced resin film rather than the mixing ratio during production.

[0025] The thickness of the resin film of the present embodiment is not particularly limited and can be appropriately selected according to the purpose. For example, it can be 5 μm or more and 100 μm or less. Preferably, it is 10 μm or more and 80 μm or less.

[0026] (Resin) The resin film of the present embodiment (and the resin composition constituting the resin film, the same shall apply hereinafter) contains one or more resins selected from polyamide-imide resin, polyamide resin, polyimide resin, polyarylate resin, polyethersulfone resin, and polycarbonate resin. In any case of using these resins, yellowing caused by the manufacturing process can be suppressed. In particular, in the resin film of the present embodiment, from the viewpoint of obtaining a resin film excellent in both elastic modulus and flexibility, it is preferable that the resin is one or two selected from polyamide-imide resin and polyamide resin.

[0027] 〔Polyamide-imide resin〕 The polyamide-imide resin is, for example, a resin obtained by reacting a diamine compound, a tetracarboxylic acid compound, and a dicarboxylic acid compound, which are monomer components. Specifically, the polyamide-imide resin is obtained by reacting a diamine compound and a tetracarboxylic acid compound to synthesize a polymer having an imide precursor structure, and then reacting the polymer with a dicarboxylic acid compound to synthesize a copolymer having an imide precursor structure and an amide structure, and then subjecting the imide precursor structure in the copolymer to a ring-closing reaction (imidation). Further, a diamine compound and a tetracarboxylic acid compound may be reacted to synthesize a polymer having an imide precursor structure, the imide precursor may be subjected to a ring-closing reaction, and then reacted with a dicarboxylic acid compound to synthesize a copolymer (polyamide-imide resin) having an imide structure and an amide structure.

[0028] That is, the polyamide-imide resin has a structure in which a residue obtained by reacting a diamine compound and a tetracarboxylic acid compound is bonded via an imide structure, and a residue obtained by reacting a dicarboxylic acid compound via an amide structure is bonded.

[0029] The polyamideimide resin preferably contains, as a residue obtained by reacting the above diamine compound and tetracarboxylic acid compound, at least one structure selected from the group consisting of a structure in which a fluorine atom, an aliphatic ring, and aromatic rings are linked by an alkylene group which may be substituted with a sulfonyl group or a fluorine atom.

[0030] Examples of the above diamine compound used in the synthesis of the polyamideimide resin include aliphatic diamines, aromatic diamines, and mixtures thereof. Here, the "aromatic diamine" refers to a diamine in which an amino group is directly bonded to an aromatic ring, and a part of its structure may contain an aliphatic group or other substituents. This aromatic ring may be a monocyclic ring or a condensed ring, and examples include a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring, but are not limited thereto. Among these, a benzene ring is preferred. The "aliphatic diamine" refers to a diamine in which an amino group is directly bonded to an aliphatic group, and a part of its structure may contain an aromatic ring or other substituents. The diamine compound may be used alone or in combination of two or more.

[0031] Examples of the aliphatic diamine include acyclic aliphatic diamines such as hexamethylenediamine; cyclic aliphatic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, norbornanediamine, 4,4'-diaminodicyclohexylmethane; and the like. The aliphatic diamine may be used alone or in combination of two or more.

[0032] Examples of the aromatic diamine include aromatic diamines having one aromatic ring such as p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, 9,9-bis(4-amino-3-fluorophenyl)fluorene and the like, which are aromatic diamines having two or more aromatic rings. The aromatic diamine may be used alone or in combination of two or more kinds.

[0033] Among the above diamine compounds, from the viewpoint of improving the colorless transparency and elasticity as a film, one or more selected from the group consisting of aromatic diamines having a biphenyl structure, specifically, one or more selected from the group consisting of 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl, and 4,4'-diaminodiphenyl ether are preferably used. Further, among the above diamine compounds, from the viewpoint of more easily improving the colorless transparency, a diamine having a biphenyl structure and having a part or all of the hydrogen atoms on the aromatic ring substituted with a substituent selected from a fluorine group, a trifluoromethyl group, or a trifluoromethoxy group, specifically, 2,2'-bis(trifluoromethyl)benzidine is more preferably used.

[0034] Examples of the tetracarboxylic acid compound used in the synthesis of the polyamideimide resin include tetracarboxylic acids or tetracarboxylic acid derivatives. Examples of the tetracarboxylic acid derivatives include anhydrides of tetracarboxylic acids, preferably dianhydrides, acid chlorides, and the like. Examples of the tetracarboxylic acid compounds also include aromatic tetracarboxylic acids and their anhydrides, preferably aromatic tetracarboxylic acid compounds such as their dianhydrides; aliphatic tetracarboxylic acid compounds and their anhydrides, preferably aliphatic tetracarboxylic acid compounds such as their dianhydrides. These tetracarboxylic acid compounds may be used alone or in combination of two or more.

[0035] Specific examples of the aromatic tetracarboxylic dianhydride include non-condensed polycyclic aromatic tetracarboxylic dianhydrides, monocyclic aromatic tetracarboxylic dianhydrides, and condensed polycyclic aromatic tetracarboxylic dianhydrides. Examples of the non-condensed polycyclic aromatic tetracarboxylic dianhydride include 4,4'-oxydiphthalic dianhydride (sODPA), 3,4-oxydiphthalic dianhydride (aODPA), 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic dianhydride (BPADA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (sBPDA), 2,2',3,3'-biphenyltetracarboxylic dianhydride (aBPDA), 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic dianhydride, 4,4'-(m-phenylenedioxy)diphthalic dianhydride, and the like. Examples of the monocyclic aromatic tetracarboxylic dianhydride include 1,2,4,5-benzenetetracarboxylic dianhydride, and examples of the condensed polycyclic aromatic tetracarboxylic dianhydride include 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0036] Examples of the aliphatic tetracarboxylic dianhydrides include cyclic or acyclic aliphatic tetracarboxylic dianhydrides. The cyclic aliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure. Specific examples thereof include cycloalkane tetracarboxylic dianhydrides such as 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclopentanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3’,4,4’-tetracarboxylic dianhydride (HBPDA), and their position isomers. These cyclic aliphatic tetracarboxylic dianhydrides may be used alone or in combination of two or more. Specific examples of the acyclic aliphatic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydride and 1,2,3,4-pentanetetracarboxylic dianhydride. These acyclic aliphatic tetracarboxylic dianhydrides may be used alone or in combination of two or more. Further, a cyclic aliphatic tetracarboxylic dianhydride and an acyclic aliphatic tetracarboxylic dianhydride may be used in combination.

[0037] Among the above tetracarboxylic acid compounds, from the viewpoint of improving the flexural resistance and optical properties as a film, an aromatic tetracarboxylic dianhydride in which some or all of the hydrogen atoms on the aromatic ring are substituted with a substituent selected from a fluoro group, a trifluoromethyl group, or a trifluoromethoxy group, specifically, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), and a tetracarboxylic dianhydride having a biphenyl structure or an alicyclic hydrocarbon structure, specifically, 3,3',4,4'-biphenyltetracarboxylic dianhydride (sBPDA), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride (HBPDA), it is preferable to use a combination of one selected from the group consisting of them, and (6FDA: any one of sBPDA, CBDA, HBPDA) is more preferably 1:2 as a molar ratio.

[0038] Among the above tetracarboxylic acid compounds, from the viewpoint of improving transparency and adhesion without impairing various properties such as heat resistance and mechanical strength as a film, 3,4-oxydiphthalic dianhydride (aODPA) and at least one selected from the group consisting of 4,4'-oxydiphthalic dianhydride (sODPA), 2,2',3,3'-biphenyltetracarboxylic dianhydride (aBPDA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), and 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) are preferably used in combination.

[0039] Examples of the above dicarboxylic acid compound used for the synthesis of the polyamideimide resin include a dicarboxylic acid or a dicarboxylic acid derivative. Examples of the dicarboxylic acid derivative include an acid chloride or an ester form of the dicarboxylic acid. The dicarboxylic acid compound may be used alone or in combination of two or more.

[0040] Specific examples of the dicarboxylic acid compound include, for example, 1,3 - cyclobutanedicarboxylic acid, 1,3 - cyclopentanedicarboxylic acid, 1,4 - cyclohexanedicarboxylic acid, 4,4'-oxybisbenzoic acid, terephthalic acid, isophthalic acid, 2,6 - naphthalenedicarboxylic acid, 1,5 - naphthalenedicarboxylic acid, 1,4 - naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, compounds in which two cyclohexanecarboxylic acids or two benzoic acids are linked by a single bond, -CH 2 -, -C(CH 3 ) 2 -, -C(CF 3 ) 2 -, -SO 2 - or a phenylene group, such as alicyclic dicarboxylic acids or aromatic dicarboxylic acids and their derivatives (e.g., acid chlorides, acid anhydrides); aliphatic dicarboxylic acid compounds such as dicarboxylic acid compounds of chain hydrocarbons having 8 or less carbon atoms and their derivatives (e.g., acid chlorides, ester forms), etc. These dicarboxylic acid compounds may be used alone or in combination of two or more.

[0041] Among the above dicarboxylic acid compounds, from the viewpoint of improving the elongation at break and elastic modulus as a film, it is preferable to use terephthalic acid, 4,4'-oxybisbenzoic acid or their derivatives, particularly terephthalic acid chloride (sometimes denoted as TPC) or 4,4'-oxybis(benzoyl chloride) (sometimes denoted as DEDC).

[0042] In the synthesis of polyamideimide resin, the composition ratio of monomer components (diamine compound:tetracarboxylic acid compound:dicarboxylic acid compound) is preferably 7:0.5 to 4:3 to 6.5, more preferably 7:1.5 to 3.5:3.5 to 5.5, and particularly preferably 7:2.5 to 3.5:3.5 to 4.5 in terms of molar ratio. According to the composition ratio of the above-mentioned monomer components, the composition ratio (molar ratio) of the imide structure and the amide structure in the structure of the polyamideimide resin is preferably 0.5 to 4:3 to 6.5, more preferably 1.5 to 3.5:3.5 to 5.5, and particularly preferably 2.5 to 3.5:3.5 to 4.5. By having the composition ratio of the imide structure and the amide structure within the above-mentioned composition ratio range, excellent flexibility and high elasticity can be achieved in a well-balanced manner.

[0043] In the ring-closing reaction (imidation) of the imide precursor in the synthesis of polyamideimide resin, either thermal imidization by adding an azeotropic solvent (e.g., toluene, xylene, etc.) that forms an azeotrope with water and heating, or chemical imidization using a condensing agent and a reaction accelerator can be used. However, chemical imidization is preferred because it is easier to maintain colorless transparency.

[0044] Examples of the condensing agent used for chemical imidization include acid anhydrides such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride, and phosphite esters such as triethyl phosphite, triethyl phosphite, tributyl phosphite, dimethyl phosphite, diethyl phosphite, and triphenyl phosphite. These condensing agents may be used alone or in combination of two or more.

[0045] Examples of the reaction accelerator used for chemical imidization include triethylamine, diisopropylethylamine, N-methylpiperidine, pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 3-ethylpyridine, 3,5-dimethylpyridine, 3,5-diethylpyridine, isoquinoline, imidazole, 1-methylimidazole, 2-methylimidazole, and 1,2-dimethylimidazole. These reaction accelerators may be used alone or in combination of two or more.

[0046] For the synthesis of polyamideimide resin, an organic solvent can be used. Such an organic solvent is not particularly limited as long as it is inert to the reaction. For example, N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, m-cresol, γ-butyrolactone, cyclopentanone, cyclohexanone, tetrahydrofuran, etc. can be mentioned. These organic solvents may be used alone or in combination of two or more.

[0047] As the reaction conditions for the synthesis of polyamideimide resin, the temperature can be 10 to 50 °C and the time can be 1 to 27 hours. Also, from the viewpoint of maintaining colorless transparency, it is preferable to synthesize under a nitrogen atmosphere.

[0048] The weight average molecular weight (Mw) of the polyamideimide resin is preferably in the range of 50,000 to 1,000,000, more preferably in the range of 80,000 to 800,000, and even more preferably in the range of 110,000 to 600,000 from the viewpoint of improving the elastic modulus and elongation at break. In this specification, the weight average molecular weight (Mw) is a value measured by GPC (gel permeation chromatography) and calculated by polystyrene conversion, and specifically, it is measured by the method described in the examples.

[0049] [Polyamide resin] The polyamide resin is, for example, a resin obtained by reacting a diamine compound and a dicarboxylic acid compound which are monomer components. That is, the polyamide resin is, for example, a resin having an amide structure formed by the reaction of a diamine compound and a dicarboxylic acid compound. Also, the polyamide resin is different from the polyamideimide resin in that the repeating units constituting it do not substantially have an imide structure. Further, the polyamide resin preferably has a structure in which the monomer components constituting it do not contain a repeating structure other than the amide structure substantially and consists of an amide structure.

[0050] As for the diamine compound used for the synthesis of the polyamide resin, it is the same as those already described (including examples and preferred examples) for the diamine compound used for the synthesis of the polyamide-imide resin. The diamine compound may be used alone or in combination of two or more.

[0051] Among the above diamine compounds, from the viewpoint of improving the colorless transparency and elasticity as a film, one or more selected from the group consisting of aromatic diamines having a biphenyl structure, specifically, one or more selected from the group consisting of 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl and 4,4'-diaminodiphenyl ether are preferably used. Further, among the above diamine compounds, from the viewpoint of more easily improving the colorless transparency, a diamine having a biphenyl structure and having a part or all of the hydrogen atoms on the aromatic ring substituted with a substituent selected from a fluoro group, a trifluoromethyl group, or a trifluoromethoxy group, specifically, 2,2'-bis(trifluoromethyl)benzidine is more preferably used.

[0052] As for the dicarboxylic acid compound used for the synthesis of the polyamide resin, it is the same as those already described (including examples and preferred examples) for the dicarboxylic acid compound used for the synthesis of the polyamide-imide resin. The dicarboxylic acid compound may be used alone or in combination of two or more.

[0053] Among the above dicarboxylic acid compounds, from the viewpoint of improving the elongation at break and elastic modulus as a film, terephthalic acid, 4,4'-oxybisbenzoic acid or their derivatives, particularly, terephthaloyl chloride (TPC) or 4,4'-oxybis(benzoyl chloride) (DEDC) are preferably used. Also, it is preferable to use TPC and DEDC in combination as the above dicarboxylic acid compound.

[0054] The polyamide resin can be produced by a method known as a method for producing polyamide. For example, a solution polymerization method, an interfacial polymerization method, a melt polymerization method, a solid-phase polymerization method, etc. can be used. In particular, for the production of aromatic polyamide resins, a solution polymerization method and an interfacial polymerization method can be preferably used.

[0055] Specifically, for example, a polyamide resin can be synthesized by a solution polymerization method from a diamine compound and an acid chloride of a dicarboxylic acid as a dicarboxylic acid compound. In this case, the reaction can be carried out in an aprotic organic polar solvent. In this reaction, hydrogen chloride is by-produced. When neutralizing this, inorganic neutralizing agents such as calcium hydroxide, calcium carbonate, lithium carbonate, and organic neutralizing agents such as 1,2-butylene oxide, ethylene oxide, propylene oxide, ammonia, and pyridine can be used.

[0056] Examples of the aprotic organic polar solvent include sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide; formamide-based solvents such as N,N-dimethylformamide and N,N-diethylformamide; acetamide-based solvents such as N,N-dimethylacetamide and N,N-diethylacetamide; pyrrolidone-based solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone; hexamethylphosphoramide; γ-butyrolactone, etc. These aprotic organic polar solvents may be used alone or in combination of two or more. Also, aromatic hydrocarbons such as xylene and toluene can be used. Furthermore, for the purpose of promoting the dissolution of the polymer, a salt of an alkali metal or alkaline earth metal of 50% by mass or less can be added to the above solvent.

[0057] When using a polyamide resin, from the viewpoint of improving the colorless transparency of the film, it is preferable to terminate the ends of the polyamide resin. Examples of the compound used for end-capping the polyamide resin include acetyl chloride, benzoyl chloride, substituted benzoyl chloride, acetic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, 4-ethynylaniline, 4-phenylethynylphthalic anhydride, maleic anhydride, and the like.

[0058] As the reaction conditions for the synthesis of the polyamide resin, the temperature can be 10 to 50 °C and the time can be 10 minutes to 27 hours. Also, from the viewpoint of maintaining colorless transparency, it is preferable to synthesize under a nitrogen atmosphere.

[0059] From the viewpoint of improving mechanical properties, the polyamide resin preferably has a number average molecular weight (Mn) of 5,000 or more and 200,000 or less, and more preferably 10,000 or more and 180,000 or less.

[0060] From the viewpoint of improving mechanical properties, the polyamide resin preferably has a weight average molecular weight (Mw) of 10,000 or more and 1,000,000 or less, more preferably 50,000 or more and 500,000 or less, and even more preferably 100,000 or more and 300,000 or less.

[0061] The polyamide resin preferably has a dispersity (Mw / Mn) of 1.0 or more and 20 or less, more preferably 1.0 or more and 15 or less, and even more preferably 1.0 or more and 4.0 or less.

[0062] [Polyimide resin] A polyimide resin is a resin obtained, for example, by reacting diamine compounds and tetracarboxylic acid compounds as monomer components. That is, a polyimide resin is a resin having an imide structure formed by the reaction of, for example, a diamine compound and a tetracarboxylic acid compound. Further, the polyimide resin differs from the polyamideimide resin in that the repeating units constituting the resin do not substantially have an amide structure. Further, the structure that binds the monomer components constituting the polyimide resin preferably contains no repeating structure other than the imide structure and consists of an imide structure.

[0063] The diamine compounds used in the synthesis of the polyimide resin are the same as those described above (including examples and preferred examples) for the diamine compounds used in the synthesis of the polyamideimide resin. The diamine compounds may be used alone or in combination of two or more.

[0064] The tetracarboxylic acid compounds used in the synthesis of the polyimide resin are the same as those described above (including examples and preferred examples) for the tetracarboxylic acid compounds used in the synthesis of the polyamideimide resin. The tetracarboxylic acid compounds may be used alone or in combination of two or more.

[0065] The polyimide resin can be produced by a method known as a method for producing polyimide. For example, after synthesizing an imide precursor (polyamic acid resin) by reacting the tetracarboxylic acid compound and the diamine compound, it can be produced by performing a ring-closing reaction (imidization) of the imide precursor. The conditions for the ring-closing reaction are the same as those described above (including examples and preferred examples) as the conditions for the ring-closing reaction of the imide precursor in the synthesis of the polyamideimide resin.

[0066] The weight average molecular weight (Mw) of the polyimide resin is preferably in the range of 50,000 to 1,000,000, more preferably in the range of 80,000 to 800,000, and still more preferably in the range of 110,000 to 600,000 from the viewpoint of improving the elastic modulus and the elongation at break point.

[0067] [Polyarylate resin] The polyarylate resin is an amorphous aromatic polyester polymer having a structure containing an aromatic dicarboxylic acid residue and a divalent phenol residue. Such a polyarylate resin can be produced, for example, using an aromatic dicarboxylic acid or its derivative and a divalent phenol or its derivative. Further, the polyarylate resin can be produced by methods such as a solution polymerization method, a melt polymerization method, and an interfacial polymerization method.

[0068] Regarding the polyarylate resin, examples of the raw materials for introducing the aromatic dicarboxylic acid residue include aromatic dicarboxylic acids and their derivatives.

[0069] Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, chlorophthalic acid, nitrophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, methyl terephthalic acid, 4,4'-biphenyldicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-bis(4-carboxyphenoxy)ethane, 5-sodium sulfoisophthalic acid, diphenic acid, and the like. Examples of the derivative of the aromatic dicarboxylic acid include esterified products and acid chlorides of the above aromatic dicarboxylic acids having an alkyl group with 1 to 3 carbon atoms.

[0070] Among these, as the raw materials for introducing aromatic dicarboxylic acid residues, terephthalic acid, isophthalic acid, and their derivatives are preferable. Also, from the viewpoint of the balance between heat resistance and fluidity, it is more preferable to use both terephthalic acid or its derivatives and isophthalic acid or its derivatives as the raw materials for introducing aromatic dicarboxylic acid residues. In this case, the mixing molar ratio (terephthalic acid / isophthalic acid) can be arbitrary within the range of 100 / 0 to 0 / 100, but is preferably 90 / 10 to 10 / 90. Within such a range, the resulting polyarylate resin becomes more amorphous and has more excellent heat resistance. From the same viewpoint, the mixing molar ratio (terephthalic acid / isophthalic acid) is more preferably in the range of 70 / 30 to 30 / 70, and even more preferably in the range of 55 / 45 to 45 / 55.

[0071] Regarding polyarylate resins, examples of the raw materials for introducing divalent phenol residues include bisphenols. Examples of bisphenols include resorcinol, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl methane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and the like.

[0072] Among these, as the raw material for introducing divalent phenol residues, it is preferable to use 2,2-bis(4-hydroxyphenyl)propane, and it is more preferable to use only this.

[0073] Examples of commercially available polyarylate resins include, for example, Vectran (registered trademark) manufactured by Kuraray Co., Ltd., U Polymer (registered trademark) manufactured by Unitika Ltd., and Unifier (registered trademark) manufactured by Unitika Ltd.

[0074] [Polyethersulfone resin] A polyethersulfone resin is a resin having an aromatic group in the main chain and having an oxy group and a sulfonyl group as linking groups of the aromatic group. A polyethersulfone resin is usually produced by polycondensing a dihalodiphenyl compound and a dihydric phenol compound in the presence of an alkali metal compound in an organic solvent, or by polycondensing an alkali metal disalt of a dihydric phenol and a dihalodiphenyl compound. A polyethersulfone resin typically has the following formula (X1): [Chemical formula] [In the above formula (X1), Ar represents a divalent group having an aromatic ring selected from the group of the following formula (X2): [Chemical formula] Y represents a single bond, a sulfonyl group (-SO 2 -), a 2,2-propylidene group (-C(CH 3 ) 2 -), or an oxy group (-O-). It has a structural unit of ]. In the structural unit of the above formula (X1), some of the hydrogen atoms bonded to the aromatic ring may be substituted with a halogen atom, a lower alkyl group having about 1 to 3 carbon atoms, a lower alkoxy group having about 1 to 3 carbon atoms, or a phenyl group.

[0075] The above organic solvent used in the production of the polyethersulfone resin is preferably a polar solvent. Examples of such organic solvents include sulfoxide solvents such as dimethyl sulfoxide; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone; piperidone solvents such as N-methyl-2-piperidone; imidazolidinone solvents such as 1,3-dimethyl-2-imidazolidinone; and furthermore, hexamethylphosphoramide, γ-butyrolactone, sulfolane, diphenyl ether, dimethyl sulfoxide, diphenyl sulfone, and the like. Such organic solvents may be used alone or as a mixed solvent of two or more.

[0076] Examples of the above alkali metal compound used in the production of the polyethersulfone resin include alkali metal carbonates, alkali metal hydroxides, alkali metal hydrides, alkali metal alkoxides, and the like. Among these, as the above alkali metal compound, anhydrous alkali metal carbonates such as potassium carbonate and sodium carbonate are preferable.

[0077] Examples of the above dihalodiphenyl compound include dihalodiphenyl compounds having a sulfonyl group. More specifically, dihalodiphenyl sulfones such as 4,4'-dichlorodiphenyl sulfone and 4,4'-difluorodiphenyl sulfone; bis(halogenophenylsulfonyl)benzenes such as 1,4-bis(4-chlorophenylsulfonyl)benzene and 1,4-bis(4-fluorophenylsulfonyl)benzene; bis(halogenophenylsulfonyl)biphenyls such as 4,4'-bis(4-chlorophenylsulfonyl)biphenyl and 4,4'-bis(4-fluorophenylsulfonyl)biphenyl; and the like. These dihalodiphenyl compounds may be used alone or in combination of two or more. Among these, from the viewpoint of easy availability, 4,4'-dichlorodiphenyl sulfone or 4,4'-difluorodiphenyl sulfone is more preferable as the dihalodiphenyl compound, and 4,4'-dichlorodiphenyl sulfone is particularly preferable.

[0078] Examples of the above-mentioned diphenol compounds include hydroquinone, catechol, resorcinol, and 4,4'-biphenol. Further, examples of the diphenol compounds include bis(4-hydroxyphenyl)alkanes such as 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)methane, and 2,2-bis(4-hydroxyphenyl)ethane; dihydroxydiphenylsulfones such as 4,4'-dihydroxydiphenylsulfone; dihydroxydiphenyl ethers such as 4,4'-dihydroxydiphenyl ether; or those in which some of the hydrogen atoms bonded to these benzene rings are substituted with lower alkyl groups such as methyl group, ethyl group, and propyl group, lower alkoxy groups such as methoxy group, ethoxy group, and propyloxy group, or halogen atoms such as chlorine atom, bromine atom, and fluorine atom. These diphenol compounds may be used alone or in combination of two or more. Among these, from the viewpoints of price and availability, the diphenol compounds are preferably hydroquinone, 4,4'-biphenol, 2,2-bis(4-hydroxyphenylpropane), 4,4'-dihydroxydiphenyl ether, or 4,4'-dihydroxydiphenylsulfone, and the group of the following formula (X3): [Chemical formula] [In the above formula (X3), Y is the same as described above.] Bisphenols selected therefrom are more preferable, and 4,4'-dihydroxydiphenylsulfone is particularly preferable.

[0079] Examples of commercially available polyethersulfone resins include, for example, Sumika Excel PES series manufactured by Sumitomo Chemical Co., Ltd., PES series manufactured by Mitsui Chemicals, Inc., Ultrason E series manufactured by BASF Japan Ltd., Radel A series manufactured by Solvay Advanced Polymers, LLC, and the like.

[0080] [Polycarbonate resin] A polycarbonate resin is a resin having a carbonic acid ester structure (-O-(C=O)-O-) in its molecular structure. Examples of such polycarbonate resins include reaction products of polyhydric phenol compounds and phosgene or carbonic acid ester compounds.

[0081] Examples of the polyhydric phenol compounds include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bisphenol A, bisphenol C, bisphenol E, bisphenol F, bisphenol M, bisphenol P, bisphenol S, bisphenol Z, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-phenyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl oxide, and the like. Among these, as the polyhydric phenol compounds, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, and bisphenol A are preferred.

[0082] Examples of the carbonic acid ester compounds include diphenyl carbonate, bis(chlorophenyl) carbonate, dinaphthyl carbonate, bis(diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and the like. Among these, as the carbonic acid ester compounds, bis(diphenyl) carbonate, dimethyl carbonate, and diethyl carbonate are preferred.

[0083] Examples of commercially available polycarbonate resins include, for example, Panlite L-1250WP and Panlite SP-1516 manufactured by Teijin Limited; Upizer EP-5000, Upizer EP-4000, Upizer PCZ-200, Upizer PCZ-400, Upizer PCZ-500, Upizer PCZ-800, Upizer FPC-2136, Upizer FPC-0330, and Upizer FPC-0220 (where "Upizer" is a registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc.; Caliber 301-30 manufactured by Sumika Polycarbonate Limited; QPAC25, QPAC40, and QPAC100 manufactured by EMPOWER MATERIALS, Inc.; and the like.

[0084] (Phosphorus compound) The resin film of this embodiment contains a predetermined phosphorus compound. Such a predetermined phosphorus compound is one or more phosphorus compounds selected from phosphonic acid compounds represented by the general formula (1), orthophosphate esters represented by the general formula (2), and condensed phosphate esters represented by the general formula (3). By using these predetermined phosphorus compounds, the action of replacing a part of the solvent and, consequently, the effect of suppressing yellowing can be obtained due to the specific action of the phosphorus compound.

[0085] The phosphonic acid compound is one of the predetermined phosphorus compounds in the present invention and is represented by the following general formula (1): [Chemical formula] [In the general formula (1), R 1 and R 2 are each independently a hydrogen or an alkyl group or an aryl group which may have a substituent, and R 3 is an alkyl group or an aryl group which may have a substituent.]. The phosphonic acid compound may be used alone or in combination of two or more.

[0086] In the above general formula (1), R 1 and R 2is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably all are methyl groups. Further, in the above general formula (1), R 3 is preferably an aryl group, and more preferably a phenyl group, from the viewpoint of obtaining a higher desired effect.

[0087] The orthophosphate ester is one of the predetermined phosphorus compounds in the present invention, and has the following general formula (2): [Chemical formula] [In the general formula (2), R 4 ~R 6 are each independently a hydrogen atom or an alkyl group or an aryl group which may have a substituent, provided that one or more of R 4 ~R 6 are not hydrogen]. The orthophosphate ester may be used alone or in combination of two or more.

[0088] In the above general formula (2), it is preferable that all of R 4 ~R 6 are not hydrogen. Further, from the viewpoint of obtaining a higher desired effect, R 4 ~R 6 are each independently more preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, and still more preferably an alkyl group having 2 to 4 carbon atoms or a phenyl group. Further, it is even more preferable that all of R 4 ~R 6 are the same.

[0089] The condensed phosphate ester is one of the predetermined phosphorus compounds in the present invention, and has the following general formula (3): [Chemical formula] [In the general formula (3), R 7 and R 8Each independently represents an alkyl group or an aryl group which may have a substituent, X represents a divalent organic group containing at least one aromatic ring, and n represents an integer of 1 or more. The condensed phosphate ester may be used alone or in combination of two or more.

[0090] In the general formula (3) above, n is preferably 1. Further, in the general formula (3), R 7 and R 8 are preferably an aryl group, more preferably a phenyl group, from the viewpoint of obtaining a higher desired effect. Further, in the general formula (3), X preferably contains one or two aromatic rings from the viewpoint of obtaining a higher desired effect.

[0091] Among these, from the viewpoint of suppressing the deterioration of various properties such as mechanical properties and thermal properties that may occur when a large amount of the phosphorus compound remains in the resin film after heat drying, the phosphorus compound having high volatility, specifically, the phosphonic acid compound represented by the general formula (1) above, and one or more selected from the orthophosphate esters represented by the general formula (2) above are preferable.

[0092] The resin film of the present embodiment requires that the content of the phosphorus compound (in the case of two or more, the total content) is more than 0 part by mass and 25 parts by mass or less with respect to 100 parts by mass of the resin. When the content of the phosphorus compound is within the above range, the effect of replacing at least a part of the solvent, and thus the effect of suppressing yellowing can be significantly obtained, and various properties required for the film can also be maintained. From the same viewpoint, the content of the phosphorus compound with respect to 100 parts by mass of the resin is preferably 2 parts by mass or more, more preferably 3.5 parts by mass or more, still more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, even more preferably 7.5 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 13 parts by mass or less. In addition, the content of the phosphorus compound relative to 100 parts by mass of the resin in the resin film can be measured using NMR, and specifically, it can be measured according to the procedure described in the examples.

[0093] (Solvent) In the resin film of the present embodiment, a solvent may typically remain due to the manufacturing process.

[0094] The above solvent is not particularly limited, and a known solvent, particularly an organic solvent, can be used. Examples of the above solvent include amide solvents, ester solvents, ether solvents, ketone solvents, sulfoxide solvents, alcohol solvents, etc. Among these, from the viewpoint that the action of replacing with the above-mentioned phosphorus compound and thus the action of suppressing yellowing are more likely to occur, amide solvents, ester solvents, and ether solvents can be preferably used. The above solvent may be a single species or a combination of two or more species. Examples of amide solvents include N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), etc. Examples of ester solvents include γ-butyrolactone (GBL), ε-caprolactone, ethyl acetate, etc. Examples of ether solvents include tetrahydrofuran, diethylene glycol dimethyl ether (diglyme), dioxane, etc.

[0095] The resin film of the present embodiment requires that the content (remaining amount) of the solvent (in the case of two or more species, the total content) is 2.5 parts by mass or less with respect to 100 parts by mass of the resin. By setting such a range, coloring due to oxidation of the solvent or the like can be significantly suppressed. Further, from the viewpoint of further suppressing yellowing, the content of the solvent with respect to 100 parts by mass of the resin is preferably 2.0 parts by mass or less, more preferably 1.8 parts by mass or less, still more preferably 1.5 parts by mass or less, and even more preferably 1.2 parts by mass or less. The content of the solvent with respect to 100 parts by mass of the resin in the resin film can be measured using NMR, and specifically, it can be measured according to the procedure described in the examples.

[0096] In the resin film of the present embodiment, if a certain amount of phosphorus compound (within the range of 25 parts by mass or less) is contained, due to the above-described replacement action, the inclusion of a relatively large amount of solvent (within the range of 2.5 parts by mass or less) is considered to be allowed. Based on this, in the resin film of the present embodiment, the mass ratio of the content of the solvent to the content of the phosphorus compound (content of the solvent / content of the phosphorus compound) may be 0.7 or less.

[0097] (Other components) In addition to the above-described resin, phosphorus compound, and solvent, the resin film of the present embodiment may contain other components within a range not departing from the object of the present invention. Examples of such other components include, for example, other resins other than the above-described resin, leveling agents, dispersants, surfactants, retardation adjusters, antioxidants, ultraviolet ray inhibitors, light stabilizers, plasticizers, waxes, fillers, pigments, dyes, foaming agents, defoaming agents, dehydrating agents, antistatic agents, antibacterial agents, antifungal agents, bluing agents for reducing the yellowness of the film, pH adjusters, crosslinking agents, lubricants, etc.

[0098] [Other resins] Examples of other resins other than the above-described resin include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyphenylene sulfide resin, polyether ether ketone resin, polyether imide resin, epoxy resin, phenolic resin, glass-epoxy resin, polyphenylene ether resin, acrylic resin, polyolefin resins such as polyethylene and polypropylene, and polycyclic olefins such as polynorbornene.

[0099] [Filler] In particular, the resin film of this embodiment can contain a filler. The material of such a filler is not particularly limited, and examples thereof include silica, titanium oxide, alumina (including alumina hydrate), silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, and the like. Examples of the alumina hydrate include boehmite and pseudo-boehmite. These fillers may be used alone or in combination of two or more. Among these, as the filler material, alumina (including alumina hydrate) is preferable, boehmite or pseudo-boehmite is more preferable, and pseudo-boehmite is even more preferable. That is, the filler is preferably an alumina filler, more preferably a boehmite-shaped or pseudo-boehmite-shaped alumina filler, and even more preferably a pseudo-boehmite-shaped alumina filler.

[0100] The shape of the filler is not particularly limited, and examples thereof include fibrous, spherical, plate-like, columnar, prismatic, scaly, and irregular shapes. Among these, the shape of the filler is preferably fibrous. That is, the filler is preferably a fibrous filler. In this case, it is considered that each fibrous filler is arranged in a lattice pattern with each other in the resin composition, so that it is possible to suppress coloring, turbidity, and a decrease in flexibility, and impart an effect of increasing elasticity. In addition, compared with spherical or irregular fillers, the fibrous filler can impart an excellent anti-blocking effect without impairing light transmittance. Specifically, when the resin films of this embodiment are stacked or wound in a roll for storage, the above-described fibrous filler suppresses sticking (blocking) between the resin films, and the storage stability and workability can be improved. Note that "fibrous" refers to a shape having an aspect ratio (filler length / filler diameter) of 5 or more.

[0101] Further, it is preferable that the fibrous filler has an average fiber diameter of 1 to 30 nm and an average fiber length of 100 to 4,000 nm. If such fibrous fillers are dispersed, each fibrous filler arranges in a lattice pattern with each other in the resin composition, thereby enhancing the effects of suppressing the above-described coloring, turbidity, and decrease in flexibility, and enhancing the effect of increasing high elasticity. From the same viewpoint, the average fiber diameter of the fibrous filler is more preferably 2 nm or more, still more preferably 3 nm or more, and more preferably 25 nm or less, still more preferably 20 nm or less. Further, from the same viewpoint, the average fiber length of the fibrous filler is more preferably 300 nm or more, still more preferably 500 nm or more, and more preferably 3,000 nm or less, still more preferably 2,000 nm or less.

[0102] The "average fiber diameter" and "average fiber length" are measured by dissolving the resin film in a good solvent of the resin constituting the resin film (for example, methyl isobutyl ketone (MIBK) or dimethylacetamide (DMAc)), diluting it by ten thousand times, dropping one drop onto a cover glass (cover glass trophy, manufactured by Matsunami Glass Ind., Ltd.), drying it at 50 ° C, and then observing it with an electron microscope image (for example, a 10,000-fold observation image using FE-SEM manufactured by Hitachi High-Tech). In addition, as long as the fibrous filler to be measured can be visually recognized as a single fiber in the electron microscope image, it may be in any state of a single fiber or a fiber bundle in which a plurality of single fibers are aggregated. The average measured length value of the diameter in the short side direction of 50 fibrous fillers arbitrarily selected in the electron microscope image is defined as the "average fiber diameter", and the average measured length value in the long side direction is defined as the "average fiber length".

[0103] The above fibrous filler can be blended and stirred in the form of powder or dispersion (sol) in the above-mentioned predetermined resin, and kneaded as necessary, so as to adjust the dispersion state in the resin composition, that is, the "average fiber diameter" and the "average fiber length". For example, stirring or kneading can be carried out using stirrers such as dissolvers and butterfly mixers, and kneaders such as roll mills and bead mills. However, it can be adjusted according to various conditions such as the rotation speed of the stirrer / kneader, the shape of the stirring blade / kneading device, the stirring / kneading time, the stirring / kneading temperature, the bead filling rate, and the roll interval.

[0104] The above fibrous filler can be surface-treated or used as a dispersion (sol) dispersed in an organic solvent or the like. In this case, the dispersion state in the resin composition can be stabilized. Among them, if the dispersion state of the fibrous filler in the dispersion (sol) is adjusted to be the same as the dispersion state of the fibrous filler in the resin composition, that is, the "average fiber diameter" and the "average fiber length", a solution (dispersion), and thus a resin film can be produced with high productivity.

[0105] The method for surface-treating the fibrous filler is not particularly limited. For example, methods for surface treatment with coupling agents such as silane-based, titanate-based, aluminate-based, and zirconium aluminate-based coupling agents can be mentioned. Further, the method for preparing a dispersion of the fibrous filler is not particularly limited. For example, a method for preparing a dispersion treated with an organic sulfonic acid disclosed in JP-A No. 2008-31010 can be mentioned.

[0106] 〔Dispersant〕 When manufacturing the resin film of the present embodiment, a dispersant may be further used. That is, the resin film of the present embodiment may further contain a dispersant. In particular, such a dispersant is preferably used in combination when using the above-described filler. Examples of the dispersant include organic carboxylic acid compounds such as acetic acid, benzoic acid, terephthalic acid, citric acid, succinic acid, and lactic acid from the viewpoint of modifying the above filler and stabilizing the solution viscosity of the resin composition; organic phosphoric acid compounds and organic phosphonic acid compounds (other than the predetermined phosphorus compounds used in the present embodiment); organic sulfonic acid compounds such as benzenesulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid; organic bases such as pyridine, tetraethylamine, diisopropylethylamine, 2,6-dimethylpyridine, isoquinoline, and triethylenediamine; and the like.

[0107] (Manufacture of Resin Film) The manufacturing method of the resin film of the present embodiment is not particularly limited. For example, (1) a step of dispersing the above-described predetermined resin, the above-described predetermined phosphorus compound, and any other components (described above) in a solvent at a predetermined ratio to prepare a solution (dispersion), (2) a step of applying such a solution (dispersion) onto a substrate to obtain a coating film, (3) a step of drying such a coating film, and (4) a step of peeling the dried coating film from the substrate to obtain a film, whereby the resin film of the present embodiment can be manufactured.

[0108] When a solvent is used for the synthesis of the resin, the solvent may be used as it is.

[0109] When preparing the solution (dispersion), it is preferable to adjust the blending amount of the phosphorus compound with respect to the resin in order to manufacture the resin film of the present embodiment. Specifically, considering that not only the solvent but also the phosphorus compound can volatilize, by setting the blending amount of the phosphorus compound to 2 to 25 parts by mass with respect to 100 parts by mass of the resin, a resin film having a predetermined composition can be obtained. The blending amount of the phosphorus compound with respect to 100 parts by mass of the resin is more preferably 5 parts by mass or more, still more preferably 10 parts by mass or more, and also more preferably 20 parts by mass or less.

[0110] As means for applying a solution (dispersion) onto a substrate, conventionally known means can be applied. For example, dip coating method, flow coating method, roll coating method, bar coater method, blade coater method, screen printing method, curtain coating method, spray coating method, etc. can be mentioned.

[0111] The conditions for drying the coating film are not particularly limited and can be adjusted based on the boiling point of the solvent used, etc. For example, it is preferable to perform primary drying at 90 to 150°C for 1 to 60 minutes and secondary drying at 180 to 250°C for 1 to 60 minutes. Tertiary drying may be further performed after the secondary drying. Note that since the volatilization behavior differs depending on the phosphorus compound and solvent selected, it is preferable to appropriately adjust the drying conditions in order to obtain a resin film with a predetermined composition.

[0112] The resin film of this embodiment can be used for a wide range of applications such as packaging films and various optical films. However, since it is excellent in colorlessness, it can be particularly preferably used as a member for displays. Examples of members for displays include organic EL displays, flexible substrates, flexible panels, liquid crystal display devices, touch panels, cover windows, surface protection films, etc.

Examples

[0113] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples and can be appropriately changed without changing the gist thereof.

[0114] The phosphorus compounds used in each example are as follows: Condensed phosphate ester 1: manufactured by ADEKA CORPORATION, "ADEKA STAB FP-900L" Condensed phosphate ester 2: manufactured by ADEKA CORPORATION, "ADEKA STAB PFR" Condensed phosphate ester 3: manufactured by ADEKA CORPORATION, "ADEKA STAB FP-600" Orthophosphate ester 1 (TPhP): triphenyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) Orthophosphate 2 (TEP): Triethyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) Orthophosphate 3 (TBP): Tributyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) Phosphonic acid compound 1 (PPADM): Dimethyl phenylphosphonate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0115] The solvents used in each example are as follows: DMAc: Dimethylacetamide (amide solvent) NMP: N-Methyl-2-pyrrolidone (amide solvent) GBL: γ-Butyrolactone (ester solvent) diglyme: Diethylene glycol dimethyl ether (ether solvent)

[0116] <Synthesis of polyamideimide resin (PAI)> A 100 mL reactor was filled with 60.0 g of N,N-dimethylacetamide (DMAc), and 4.849 g (15.14 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) was added. Next, 1.007 g (3.245 mmol) of 3,4-oxydiphthalic dianhydride (aODPA) and 1.007 g (3.245 mmol) of 4,4'-oxydiphthalic dianhydride (sODPA) were added to this solution of TFMB, and the mixture was stirred at 30 °C for 2 hours to react, obtaining a solution containing a polymer having an imide precursor structure. Thereafter, 1.757 g (8.653 mmol) of terephthaloyl chloride (TPC) was added to this solution, and the mixture was stirred at 30 °C for 1.5 hours to react while maintaining the liquid temperature, obtaining a solution containing a copolymer having an imide precursor structure and an amide structure. Subsequently, 2.09 g of pyridine, 2.45 g of acetic anhydride, and 8.53 g of DMAc were added, and the mixture was stirred at 20 - 30 °C for 8 hours to obtain a polyamideimide solution. Further, 99 g of DMAc was added and stirred until uniform, and then this solution was gradually added to a container containing 4 L of methanol for precipitation. Next, the precipitated solid was filtered and pulverized, and then dried under vacuum at 80 °C for 18 hours to obtain 8.0 g of a solid powder of polyamideimide copolymer (PAI). The obtained PAI had a weight-average molecular weight of 221,000 in terms of polystyrene by GPC.

[0117] <Synthesis of polyamide resin (PA)> A 100 mL reactor was filled with 60.0 g of N,N-dimethylacetamide (DMAc), and 5.33 g (16.63 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) and 2.64 g (36.59 mmol) of 1,2-butylene oxide were added. Subsequently, 0.97 g (3.29 mmol) of 4,4'-oxybis(benzoyl chloride) (DEDC) and 2.67 g (13.17 mmol) of terephthaloyl chloride (TPC) were added to this solution of TFMB, and the mixture was stirred at 30 °C for 2 hours for reaction. Then, 0.026 g (0.33 mmol) of acetyl chloride was added to this solution, and the mixture was stirred at 30 °C for 30 minutes for reaction to obtain a solution containing a polymer (PA) having an amide structure. The obtained PA had a weight-average molecular weight of 184,000 in terms of polystyrene by GPC.

[0118] <Fabrication of film> Using the formulation shown in Tables 1 to 3, after dissolving the powder of the resin (polyamide-imide resin or polyamide resin) and the phosphorus compound in each solvent, they were dispersed and homogenized to prepare a solution for film production. Note that in Examples 1 to 10 and Comparative Example 1, the solid content concentration was 13% by mass, in Examples 11 to 13 and Comparative Examples 2 to 4, the solid content concentration was 10% by mass, and in Example 14 and Comparative Example 5, the solvent was added and adjusted so that the solid content concentration was 12% by mass. Next, this solution was applied onto a glass substrate using a table coater ("AFA-standard" manufactured by Coattech Co., Ltd.) so that the thickness after drying would be 50 μm, and then dried using an oven ("Fine Oven DH612" manufactured by Yamato Scientific Co., Ltd.) to form a film made of the resin composition. As the drying conditions, two-stage drying was performed at 120 °C for 40 minutes and then at 220 °C for 30 minutes. However, for Comparative Example 2 and Example 11 in Table 2 (examples using NMP as the solvent), three-stage drying was performed at 120 °C for 40 minutes, then at 220 °C for 30 minutes, and further at 220 °C for 30 minutes. Here, Table 1 summarizes the comparison with different types and blending amounts of the phosphorus compound, Table 2 summarizes the comparison with different types of solvents, and Table 3 summarizes the comparison with different types of resins.

[0119] The following measurements were performed on the obtained films. These results are shown in Tables 1 to 3.

[0120] (1) Measurement of the solvent content ( 1 H NMR spectrum) Each film was dissolved in dimethyl sulfoxide-d 6 and the H NMR spectrum was measured using "JNM-ECA400II" manufactured by JEOL Ltd. At that time, the signal of dimethyl sulfoxide-d 1 contained in dimethyl sulfoxide-d 6 was set as 2.5 ppm as the reference for chemical shift. 5 The integration value was analyzed with the integration value of the signal derived from the hydrogen atom in the amide group in the resin (in the case of polyamide-imide resin: around 10.8 ppm, in the case of polyamide resin: around 10.6 ppm) set as 1. Measured Measured1 From the 1H NMR spectrum, the mass of the solvent (residual amount) relative to the mass of the resin in the film was determined using the following formula (A1).

Equation

[0121] M S : Content of solvent (parts by mass / resin 100 parts by mass) MW s : Molecular weight of solvent MW rep : Molecular weight of repeating unit IR s : Integration ratio of solvent signal HN s : Number of hydrogen atoms of solvent signal HN r : Number of hydrogen atoms of resin signal

[0122] The molecular weight of the solvent (MW s ) was adopted as the following values depending on the solvent used. DMAc: 87.1 NMP: 99.13 GBL: 86.09 diglyme: 134.17

[0123] The molecular weight of the repeating unit (MW rep ) was adopted as the following values depending on the resin used. Polyamideimide resin: 512.08 Polyamide resin: 542.44

[0124] The number of hydrogen atoms of the solvent signal (HN s ) was adopted as the following values depending on the solvent used. DMAc: 3 NMP: 3 GBL: 2 diglyme: 6

[0125] The number of hydrogen atoms of the resin signal (HN r ) was adopted as the following values depending on the resin used. Polyamideimide resin: 1.14 Polyamide resin: 2

[0126] (2) Measurement of the content of phosphorus compound ( 1 H NMR spectrum) As measured above 1 From the H NMR spectrum, the mass of the phosphorus compound relative to the mass of the resin in the film was determined using the following formula (A2). [Number]

[0127] M p : Content of phosphorus compound (parts by mass / 100 parts by mass of resin) MW p : Molecular weight of phosphorus compound MW rep : Molecular weight of repeating unit IR p : Signal integration ratio of phosphorus compound HN p : Number of hydrogen atoms of phosphorus compound signal HN r : Number of hydrogen atoms of resin signal

[0128] Molecular weight of phosphorus compound (MW p ) was adopted as the following values depending on the phosphorus compound used. Condensed phosphate ester 1: 650.55 Condensed phosphate ester 2: 574.5 Condensed phosphate ester 3: 692.64 Primary phosphate ester 1 (TPhP): 326.28 Primary phosphate ester 2 (TEP): 182.15 Primary phosphate ester 3 (TBP): 266.31 Phosphonic acid compound 1 (PPADM): 186.15

[0129] Number of hydrogen atoms of phosphorus compound signal (HN p ) was adopted as the following values depending on the phosphorus compound used. Condensed phosphate ester 1: 12 Condensed phosphate ester 2: 12 Condensed phosphate ester 3:6 Orthophosphate ester 1 (TPhP):9 Orthophosphate ester 2 (TEP):9 Orthophosphate ester 3 (TBP):9 Phosphonic acid compound 1 (PPADM):3

[0130] Note that the repeating unit molecular weight (MW rep ) and the number of resin signal hydrogen atoms (HN r ) are the same as those in formula (A1).

[0131] (3) Evaluation of YI value (Yellow Index) Each film was cut into a size of 30 mm × 30 mm, and in accordance with ASTM E313-73, the YI value of each film was measured using a spectrophotometer (CM-5, manufactured by Konica Minolta Inc.). For comparison between the films, the measured YI value converted to a film thickness of 50 μm was taken as the YI value for each example. The closer the YI value is to 0, the better the colorlessness. Also, for the YI value of each example, the amount of change relative to the YI value of the reference example was calculated. If the amount of change in the YI value is a negative value, it indicates that yellowing has been suppressed.

[0132] [Table 1]

[0133] [Table 2]

[0134] [Table 3]

[0135] From Tables 1 to 3, it can be seen that when preparing a film by dispersing a resin in a solvent, by blending a predetermined phosphorus compound and optimizing the contents of the phosphorus compound and the solvent, yellowing of the film can be significantly suppressed.

Industrial Applicability

[0136] According to the present invention, it is possible to provide a resin film in which yellowing due to the manufacturing process is suppressed.

Claims

1. A resin film made of a resin composition, wherein the resin composition comprises: one or more resins selected from a polyamide-imide resin, a polyamide resin, a polyimide resin, a polyarylate resin, a polyethersulfone resin, and a polycarbonate resin; and one or more phosphorus compounds selected from the following general formula (1): 【Chemical 1】 [In general formula (1), R １ and R ２ are each independently a hydrogen or an alkyl group or an aryl group which may have a substituent, and R ３ is an alkyl group or an aryl group which may have a substituent], a phosphonic acid compound represented by the following general formula (2): 【Chemical Formula 2】 [In general formula (2), R ４ to R ６ are each independently a hydrogen atom or an alkyl group or an aryl group which may have a substituent, provided that at least one of R ４ to R ６ is not a hydrogen atom], a positive phosphate ester represented by the formula, and, the following general formula (3): [Chemical 3] [In general formula (3), R ７ and R ８ are each independently an alkyl group or an aryl group which may have a substituent, X is a divalent organic group containing at least one aromatic ring, and n is an integer of 1 or more], a condensed phosphate ester represented by and contains, the content of the phosphorus compound is more than 0 part by mass and 25 parts by mass or less with respect to 100 parts by mass of the resin, the content of the solvent is 2.5 parts by mass or less with respect to 100 parts by mass of the resin, characterized in that, a resin film.

2. The resin film according to claim 1, wherein the content of the phosphorus compound is 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin.

3. The resin film according to claim 1 or 2, wherein the solvent is one or more selected from an amide-based solvent, an ester-based solvent, and an ether-based solvent.

4. The resin film according to claim 1 or 2, wherein the resin is one or two selected from a polyamide-imide resin and a polyamide resin.

5. The resin film according to claim 1 or 2, wherein the phosphorus compound is one or more selected from a phosphonic acid compound represented by the above general formula (1) and an orthophosphate ester represented by the above general formula (2).

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